The word PAR (bull) appears 32 times in the Torah. All of them, except 4 times, the PEI is voweled with a PATACH. The other four times - all in Parshat Balak, the PEI has a KAMATZ under it. In the S'faradi way of pronouncing Hebrew, the two words are indistinguishable. But in Ashkenazis (and in the Yemenite pronunciation), the common one is PAR and the rare, in Balak only ones are PAWR. When PAR has a HEI-HAY'DI'A - which accounts for another 20 or so times, the PEI always has a KAMATZ. HA-PAWR. Or HAPAR in Israeli Hebrew. No grammatical explanation is herein offered, nor does it seem to be a "serious" mistake if a Baal Korei misreads the word. But this column is about fine-tuning and paying attention. So there you have it.

Now look in B'midbar 23:18. There's a word with a CHATAF-PATACH under a SHIN. That's kind of rare, since CHATAF-vowels usually are found under the guttural letters - ALEF, AYIN, HEI, CHET. When there is a non-G'RONIT (throat-letter) with a CHATAF-PATACH, there are three different opinions as to how to pronounce the letters. Some do it like a SH'VA NA. U-SH'MA, in this case. Some pronounce the CHATAF-PATACH, U-SHAMA. And some opinions distinguish among the situations of the specific occurrence and sometimes read it like a SH'VA NA and sometimes like a slightly shortened PATACH. (Those conditions are too complicated to include here.) Note that in this case, had there been a a SH'VA under the SHIN, as there is in SH'MA without the SHURUK-ed VAV prefixed to it, the word would be pronounced USH-MA, considering the SHIN's SH'VA to be NACH. Here it is clearly meant to stay with the MA syllable, so the word is U- SH'MA. The CHATAF-PATACH can signal that the SH'VA is atypically NA in this word.